Tuna longline and tuna pole website contributions

Tuna longline and tuna pole website contributions
1. History and description of the sector
Tuna longline:
Commercial longlining for tuna in South Africa has been documented since the 1960’s with
catches reaching ~2000 MT. Southern bluefin tuna and albacore comprised the bulk of the
catch. The fishery ceased to exist after the mid 1960’s, as a result of a poor market for low
quality bluefin and albacore tuna landed by South African fishers. Interest to target tuna
using longline gear re-emerged in 1995 when a joint venture with a Japanese vessel
confirmed that tuna and swordfish could be profitably exploited within South Africa’s
waters. 30 experimental longline permits were issued in 1997 to target tuna. The main
purpose of the fishery was to develop a large pelagic catch performance for South Africa
such that South Africa could receive equitable quotas from the Regional Fisheries
Management Organisations (RFMOs) such as the International Commission for the
Conservation of Atlantic Tuna (ICCAT) and the Indian Ocean Tuna Commission (IOTC) and the
Commission for the Conservation of Southern Bluefin Tuna (CCSBT). Catches peaked at over
2 500 t during the experimental phase of the fishery. However, swordfish comprised the
bulk of the catch in each year. Targeting of swordfish has led to sharp declines in swordfish
abundance in South Africa’s EEZ.
50 long-term rights (10 year) were made available at the end of 2005; 17 rights were issued
to the swordfish-directed fishery and 26 to the tuna-directed fishery (1 right = 1 vessel). The
primary objectives of this allocation were to develop a tuna catch performance for South
Africa and to South Africanise the fishery. Catches improved to > 3 500 t in 2005 with the
assistance of foreign flag charters. However, none of the Asian flagged vessels reflagged
South African and as a result no further provision was made for the use of foreign flag
charters in 2006. Consequently catches declined to < 500 t. In 2007 foreign flagged vessels
were allowed to fish in South Africa yet again to, a) improve the South Africa’s catch
performance, b) to transfer skills to South African crew and c) to eventually reflag South
African. To date, there are on average 10 – 15 foreign-flagged vessels taking out permits to
fish in South Africa each year.
In March 2011 the Department consolidated the tuna/swordfish longline fishery and the
pelagic shark fishery. The 6 pelagic shark vessels were absorbed into the tuna/swordfish
longline fishery. The decision to terminate the targeting of pelagic sharks was due to the
following reasons: 1) both blue and mako are threatened species as described by the IUCN;
2) substantial pelagic shark by-catch is expected in the tuna/swordfish fisheries; 3) sharks
are slow growing, mature late, have low fecundity which makes them more susceptible to
over-fishing, and 4) concerns over ecosystem effects.
As tuna and swordfish are oceanic migrants, their stocks are fished by a number of nations.
Consequently, the management of these stocks are the responsibility of RFMOs. ICCAT and
the IOTC are responsible for conducting stock assessments, devising control measures and
issuing country allocations for stocks in the Atlantic Ocean and Indian Ocean, respectively.
Tuna pole:
The tuna pole fishery has operated since 1980 and the fishing grounds are situated along the
west coast of South Africa. The tuna pole fishery traditionally targets high volume, low value
albacore Thunnus alalunga along the west coast of South Africa for canning. As there is little
value adding the fishery operates on small profit margins. Since 2003, this sector has
diversified with some vessels targeting low volume, high value yellowfin tuna T. albacares
for sashimi markets. Due to the seasonality of tuna in South Africa’s waters the tuna pole
fishery was also allowed access to snoek Thyrsites atun and yellowtail Seriola lalandi. Access
to these additional species has caused conflict with the traditional linefish sector. Some
tuna pole operators in the past have exacerbated the situation by targeting these species
only, with no or little performance on tuna. To reduce the conflict between these sectors it
was decided that tuna pole access to yellowtail would only be by means of bag limits, i.e. 10
yellowtail per person per trip. A minimum vessel size was also stipulated, i.e. only vessels ≥
10 m will be allowed into the fishery unless tuna performance is demonstrated. Access to
snoek requires further deliberation.
The fishery is managed by a TAE of 200 vessels (3 600 crew) and 200 rights were made
available in the long-term allocation process in 2005, as albacore (the primary target
species) was considered under-exploited. Annual catches of albacore have fluctuated
around 3 000 MT and is largely dependent on the availability of albacore in near-shore
waters from October to May. Due to the seasonality of the fishery, up to 40% of Rights
holders are involved in other sectors.
The four major contracting parties/ co-operating non-contracting parties/ fishing entities
actively fishing for albacore in the South Atlantic are Chinese-Taipei, South, Brazil and
Namibia. ICCAT is responsible for conducting stock assessments, devising control measures
and issuing country allocations. The stock assessment conducted in 2011 determined TAC of
24 000 MT for the south Atlantic region. South Africa was allocated 10 000 MT to share with
Namibia, and that is currently being managed on an Olympic type system.
2. Dominant and/or targeted species; bycatch species
Tuna longline targets:
•
•
Bigeye tuna (Foreign-flagged vessels)
Yellowfin tuna (Foreign-flagged vessels)
•
Swordfish (Local vessels)
Tuna/swordfish longline bycatch:
•
•
•
•
Blue sharks
Mako sharks
Seabirds (albatrosses and petrels)
Turtles
Tuna pole targets:
•
•
Albacore (high volume, low value)
Yellowfin tuna (low volume, high value)
Tuna pole bycatch:
•
•
Snoek
Yellowtail
3. Processing (frozen, canned, bait etc), and markets (local or international)
The main countries exported to include Japan, Spain, the US and the UK. They are sent fresh
or frozen (-60°C freezers onboard vessels) fish to be processed in factories for:
-
fillets (yellowfin, bigeye and albacore). Yellowfin and bigeye are exported
dressed.
canneries (albacore and skipjack tuna). Exported whole. South Africa does
not have canneries to process these fish ourselves.
sushi (yellowfin, bigeye and southern Bluefin tuna). Exported dressed
Around 80% of our catch is exported depending on the quality of the catch and international
markets. Fish of a lower quality are usually sold on the local market for less. Few fish are
required in South Africa to fulfill the sushi and fillet markets.
4. Catch history – annual catches, spatial and temporal distribution of catches
A summary of dominant target and bycatch retained catches for the last 6 years are
displayed in Figures 1 and 2. Notice the improvement in catches from 2006 to 2007 when
foreign-flagged vessels were once again given permits to fish in South Africa’s waters. The
catches of blue and mako sharks increased from 2010 to 2011 when the pelagic shark
vessels were consolidated with the tuna/swordfish longline fishery.
1000
900
Catch in metric tonnes
800
700
Blue shark
600
Mako
500
S. bluefin
400
Swordfish
300
Albacore
200
Yellowfin
100
Bigeye
0
2006
2007
2008
2009
2010
2011
Year
Figure 1. Retained tuna/swordfish longline catch from 2006 – 2011 in the Atlantic Ocean.
3500
Catch in metric tonnes
3000
2500
Blue shark
Mako
2000
S. bluefin
1500
Swordfish
1000
Albacore
Yellowfin
500
Bigeye
0
2006
2007
2008
2009
2010
2011
Year
Figure 2. Retained tuna/swordfish longline catch from 2006 – 2011 in the Indian Ocean.
4500
Catch in metric tonnes
4000
3500
3000
2500
2000
Yellowfin
1500
Albacore
1000
500
0
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
Year
Figure 3. Retained tuna pole catch from 2002 – 2011 in Atlantic and Indian Oceans.
Figure 4. The average CPUE (kg per 1000 hooks) of bigeye (orange), yellowfin (red) and swordfish
(black) from 2006 – 2011 per 1 x 1° grid block in the pelagic longline fishery.
Figure 5. The average catch of albacore (black) and yellowfin tuna (red) from 2002 - 2010 per 1 x 1°
grid block in the tuna pole fishery.
5. Socioeconomics (annual value of landed and processed catch)
Markus Burgener’s inputs…
The price per kg varies based on the availability of fish on the market, the quality of the fish
(overall meat quality, fresh/iced or frozen) and its destination. Average prices are the
following:
Albacore: R10 – R20/kg
Yellowfin tuna: R30 – R50/kg
Bigeye tuna: R50-80/kg
Swordfish: R50/kg
Southern Bluefin tuna: highest value. Varies considerably based on grading.
6. Biological characteristics of dominant species (important by-catch species too?),
including habitat and distribution, feeding, reproduction, age and growth, stock
structure, others.
Albacore species profile
Family
Scombridae
Scientific Name
Thunnus alalunga
Albacore, Longfin tuna, Longfin tunny, Albakoor,
Langvin tuna
Albacore is a highly migratory species with a wide
geographical distribution. Populations are found in the
Atlantic, Mediterranean, Indian and Pacific oceans
(ICCAT, 2004). The species prefers cooler and deeper
water from 19 – 21°C (Van Der Elst, 2010), though
dependent on a minimal dissolved oxygen content of
3.7 ml/l (Graham et al. 1989)
In South Africa schools of south Atlantic albacore
occur in larger quantities along the temperate west
coast than schools of Indian Ocean albacore along the
warmer the south east coast (Penney, 1994)
Gonochorist
Spawning season for the south Atlantic stock is in
spring-summer from September to March (ICCAT, 2004)
and October to March for the Indian ocean stock (Chen
et al. 2005)
Common Names
Global Distribution
South African Distribution
Reproductive Style
Breeding/Spawning Season
Breeding/Spawning Locality
Spawning areas in the south Atlantic are off the eastern
Brazilian coast (Beardsley 1969, Koto 1969). The main
spawning area in the Indian Ocean occurs the waters
off eastern Madagascar (Koto 1969, Shiohama 1985).
Movement
Migratory
Habitat - Adults
Age at 50% Maturity
Albacore prefer cooler temperate
Juvenile tuna from 2 to 35-40 cm FL are not caught and
this life stage remains virtually unknown (ICCAT, 2004).
From around 40 cm FL albacore start appearing in
surface fisheries. The underdeveloped swim bladder in
juveniles gives them limited vertical movement in the
water column.
Eggs and larvae are pelagic and widely distributed by
ocean currents.
Albacore are opportunistic top predators feding on
schools of sardine, anchovy, mackerel and squid
(ICCAT, 2004)
Similar diet as adults with implications on their life
history features of growth and survival.
5
Length at 50% Maturity
90cm FL
Max Age
13
Max Weight
23kg
Max Length
130cm FL
Habitat - Juveniles
Habitat - Eggs/Larvae
Feeding - Adults
Feeding - Juveniles
Yellowfin tuna species profile
Family
Scombridae
Scientific Name
Thunnus albacares
Common Names
Yellowfin tuna, Geelvin tuna, Yellowfin tunny
Global Distribution
A cosmopolitan species distributed in tropical and
subtropical open waters of the three oceans. The
geographical limits are 45°-50° N and S.
South African Distribution
The yellowfin that occur in South African waters may
be from the Atlantic and/or Indian Ocean stock.
Reproductive Style
Gonochoristic. An intermediate pattern of reproduction
implies an asynchronous development of the oocyte
(Arocha et al. 2000). One female can lay between 5 and
60 million eggs per year (Cayré et al . 1988).
Breeding/Spawning Season
October to March in the eastern Atlantic (Bard et al.
1991).
Breeding/Spawning Locality
In the eastern Atlantic the equatorial area from the
coasts of the Gabon (Gulf of Guinea) to 25 W is the
main spawning area (Bard et al. 1991).
Movement
Migratory
Habitat - Adults
Adults can reach depths of 350m but prefer to stay at
100m. The water temperature usually does not drop
more than 8°C relative to the surface temperature. It
prefers temperatures of aound 22°C and dissolved
oxygen content above 3.5ml/l-1 (Brill et al. 1999, Brill
1994 and Korsmeyer et al. 1996)
Habitat - Juveniles
More than 90% of its time is spent in depths around
100m and temperatures of around 22°C. Juveniles stay
in the equatorial region in coastal areas.
Habitat - Eggs/Larvae
Eggs (0.9 - 1.04 mm in diameter) and larvae (2.7mm)
are pelagic and widely distributed by currents.
Feeding - Adults
Adults are opportunistic top predators with a broad
food spectrum, especially in habitats with low
concentrations of organisms. Prey items include
teleosts, squid, hyperrid amphipods, Phrosina
semilunata and Cubiceps pauciradiatus .
Feeding - Juveniles
Juvenile yellowfin tuna feed prey on small mesopelagic
fish, Vinciguerria nimbari (Roger and Marchal, 1994).
Age at 50% Maturity
2
Length at 50% Maturity
108.6cm FL
Max Age
8
Max Weight
200kg
Max Length
239cm FL
Bigeye tuna species profile
Family
Scombridae
Scientific Name
Thunnus obesus
Common Names
Bigeye tuna, Bigeye tunny, Grootogg tuna
Circumglobal in tropical and subtropical waters of the
Atlantic, Indian and Pacific oceans. Absent from the
Mediterranean (Collette and Nauen 1983).
In SA this species shoals offshore and seldom
approaches the coast (van der Elst 1993).
Gonochorist, multiple broadcast spawners
Spawning season from December to January and also
in June in the eastern Indian Ocean (Nootmorn 2004).
Spawning season in the south Atlantic (Congo-Angola)
is from November to February (Rudomiotkina 1983).
Bigeye spawning takes place mostly at night, estimated
time from 18h00 to after midnight, depositing eggs
daily (Matsumoto and Miyabe 2002).
Bigeye tuna spawn in areas of increased biological
productivity near the borders of localised eddies and
local seamounts and frontal regions where
temperatures are 25-260C (Rudomiotkina 1983,
Kailola et al. 1993).
Migratory
Global Distribution
South African Distribution
Reproductive Style
Breeding/Spawning Season
Breeding/Spawning Locality
Movement
Habitat - Adults
Adults (>100cm FL) are epi and mesopelagic in open
waters. Factors affecting the distribution includes the
depth of the deep scattering layer ('false bottom'), the
temperature and the oxygen concentration (Maury
2005). Bigeye expose themselves to large temperature
changes of up to 20°C, from 25°C at the surface layer to
temperatures of ~5°C at 500 m depth. Clear diel
patterns in vertical movements were shown with
archival tagging, from 0-100 m during the day and 400500 m at night (Brill et al. 2005). Bigeye can withstand
a lower dissolved oxygen concentration than any other
tuna species, as low as 1.5 ml/l (Musyl et al. 2003).
Age at 50% Maturity
Juveniles (30-70cm FL) occupy surface waters and are
commonly found in schools at fish aggregating devices
(FADs).
Eggs and larvae are pelagic and are most frequently
found in temperatures above 28°C where salinity is
33.8 - 36.0‰ (Ambrose 1996).
Bigeye are opportunistic predators that feed on
oceanic mesopelagic communities (migratory and nonmigratory) such as cephalopods, euphausids and
mesopelagic fishes (Bertrand et al. 2002, Dagorn et al.
2000). Vertical movement to forage in the deep
scattering layer has been recorded (Dagorn et al.
2000).
Juveniles have been recorded feeding on small-sized
mesopelagic fish (Vinciguerria nimbaria ).
3
Length at 50% Maturity
100cm FL
Max Age
15
Max Weight
210
Max Length
250cm FL
Habitat - Juveniles
Habitat - Eggs/Larvae
Feeding - Adults
Feeding - Juveniles
Swordfish species profile
Family
Scientific Name
Common Names
Global Distribution
South African Distribution
Reproductive Style
Breeding/Spawning Season
Breeding/Spawning Locality
Movement
Habitat - Adults
Habitat - Juveniles
Habitat - Eggs/Larvae
Feeding - Adults
Feeding - Juveniles
Age at 50% Maturity
Xiphiidae
Xiphias gladius
Swordfish, Broadbill, Swaardvis
An oceanic species found in all oceans, including the
Mediterranean, Red Sea and North Sea (Heemstra and
Heemstra, 2004)
Most commonly found offshore but is sometimes seen
in coastal waters, generally above the thermocline
(Collette, 1995)
Gonochorist, multiple (batch) broadcast spawners
November to March in the South Atlantic. October to
April in the Indian Ocean.
Southern coast of Brazil between 20 and 30°S. Reunion
Island.
Migratory
Swordfish can tolerate a wide range of temperatures (5
- 27°C), the widest temperature tolerance than any
billfish, but is often found in surface waters at
temperatures over 13°C (Nakamura, 1985). They can
dive to depths of up to 650m.
Juvenile swordfish are commonly found in tropical and
subtropical waters and migrate to higher latitudes as
they mature (IOTC-SC14, 2011)
Eggs are pelagic. Larvae are pelagic and often found in
waters with temperatures above 24°C. They are
generally a few meters below the surface but can sink
to as deep as 30m at night (Nishikawa and Ueyanagi,
1974)
Swordfish feed on a wide variety of prey including
groundfish, pelagic fish, deep-water fish, and
invertebrates (cephalopods being the preferred prey).
They are believed to feed throughout the water column.
The diet of swordfish is known to vary
considerably, both geographically and seasonally
(Anon, 2010)
Juveniles will also opportunistically feed on fish and
invertebrates. Larvae over 10mm feed almost
exclusively on the larvae of other species.
6-7 years
Length at 50% Maturity
156cm FL
Max Age
30+ years
Max Weight
650kg
Max Length
455cm FL
7. Commercial Fishery: (What species are caught (Refer to [2]), catch areas (Refer to
[4]), gear, effort, how are they processed (Refer to [3]), economics/fishery value
(Refer to [5]?)
Table 1. The number of hooks set in the tuna/swordfish longline fishery from 2006 – 2011 in
the Indian and Atlantic Oceans.
2006
2007
2008
2009
2010
2011
Number of hooks
Atlantic
Indian
594080 442980
1258559 3234084
881153 3017020
1036607 3441229
619589 4470186
805806 5342473
Table 2. The number of catch days in the tuna pole fishery from 2002 – 2010.
2002
2003
2004
2005
2006
2007
2008
2009
2010
Number of
catch days
2863
1944
2693
2454
2331
3017
1838
2850
2693
Tuna longline gear and method description:
Pelagic longline fishing involves the use of a main line of up to 150 km in length from
which as many as 3,000 shorter branch lines, each with a baited hook, are dangled in the
water column. The mainline is kept afloat by a series of buoys attached at intervals. The
gear is passive, in that it captures any fish that happen to take the bait. Longlines
operate mostly at depths between 100 m and 150 m, but can be set as deep as 300 m
when targeting bigeye. Squid bait is generally used to target swordfish, and fish bait
(pilchard, mackerel, maasbanker) for tunas. The line is set at night when fish are closer
to the surface to feed and to reduce seabird bycatch and the line is left for up to 8 hours
to soak. Light sticks are used by the swordfish-directed fishery and these are attached
to the branch lines. Since very high quality fish is needed for sashimi, most vessels are
equipped with "flash freezers" to freeze the fish to -60°C almost immediately.
Tuna pole gear and method description:
Pole and line fishing has been practiced for centuries in several different parts of the
world. The method involves attracting a school of tuna to the side of a "bait-boat" by
chumming, spraying water or throwing live bait (sardines and anchovies) overboard. This
creates a tuna "feeding frenzy" and fish are hauled out of the water, one-by-one, using
pole and line. Tuna can then be caught with feathers (in the shape of squid), baits or live
bait. The catch consists predominantly of juvenile albacore and yellowfin though
skipjack and bigeye may also be in the school.
8. Monitoring – Fisheries Dependent; data collection and collation, catch reporting
and monitoring of landings, etc.
Permit conditions relevant to monitoring include the following:
• All fish have to be discharged in the presence of a Fishery Control Officer (FCO) who
signs off on the landing declaration.
• The relevant IOTC, ICCAT and CCSBT catch statistical documentation for the
exporting of fish has to accompany the catch.
• Catch statistic forms have to be filled out for every trip.
• Trip summaries are submitted after every trip.
• Every pelagic longline and tuna pole vessel has to be fitted with a functional vessel
monitoring system (VMS), approved by the Department.
• Tuna pole vessels are requested to submit yellowfin tuna length frequency
measurements with their catch statistic forms.
9. Monitoring – Fisheries Independent surveys, methods, timing, coverage, etc.
•
•
100% onboard observer coverage is achieved on the foreign-flagged pelagic longline
vessels. Up until March 2011 when the DAFF funded observer programme ended, up
to 20% observer coverage was achieved on local pelagic longline vessels. The tuna
pole vessels were also monitored by observers during offloading up until that time.
Monthly length frequency measurements are conducted by DAFF staff of tuna pole
catches either in port or at freezer cold stores.
•
Since the stock assessments and setting of quotas is the responsibility of the RFMOs,
the research cruises on the Ellen Khuzwayo (Voyages in 2008, 2009, 2010 and 2011)
do not directly deal with stock assessment type of sampling and data collection.
10. Assessment Strategy (eg. Per recruit, standardized cpue time series, agestructured assessment models)
The RFMOs (ICCAT, IOTC and CCSBT) conduct stock assessments of each species every two to
three years, depending on the particular species stock status. It is generally up to each
country to complete a standardised catch-per-unit-effort (CPUE) for the species/fishery. This
is plugged into models such as age structured production models (ASPMs), stock synthesis
(SS3), MultifanCL, A Stock Production Model Incorporating Covariates (ASPIC) etc. to
ascertain the Maximum Sustainable Yield (MSY), B/BMSY, SB/SBMSY, F/FMSY and to produce
Kobe plots.
11. Management strategy (OMP, TAC or TAE?)
Tuna/swordfish longline:
The South African tuna/swordfish longline fishery is relatively new, with the first commercial
rights allocated in 2005. The policy stipulated that the TAE be set at 20 swordfish-directed
vessels and 30 tuna-directed vessels. In the allocation process 18 rights were issued for the
swordfish-directed fishery and 26 for the tuna-directed fishery (1 right = 1 vessel). As large
pelagic resources are highly migratory and fished by many nations, these resources are
managed by RFMOs. South Africa received swordfish catch limits of 932 t for 2010, 962 t for
2011 and 1 001 t for 2012 from ICCAT. South Africa was also allocated southern bluefin
quotas of 40 t from CCSBT for 2010 and 2011. Merging the Pelagic Shark fishery into the
Large Pelagic (Tuna and Swordfish) fishery was realised in March 2011. Given that most tuna
and tuna-like stocks are optimally- to over-exploited and that South Africa has a vessel
capacity limit in the Indian Ocean the number of longline vessels targeting large pelagics has
been restricted to 50 at this stage of development.
Tuna pole:
The primary objective for allocating long-term rights in the tuna pole fishery in 2006 was to
improve or maintain catch performance of tuna, particularly albacore. Catch performance is
the single most important criterion for the allocation of country quotas RFMOs like ICCAT. To
achieve this objective a TAE of 200 vessels or a crew of 3 600, whichever is reached first, was
made available for the 2006 allocation. However, in recent years an increasing proportion of
the fishery has been targeting yellowfin tuna. The yellowfin tuna stock assessment
conducted by ICCAT in 2011 indicated that the stock in the Atlantic Ocean is overfished and
recommended that no additional effort be exerted on the Atlantic yellowfin stock to enable
the stock to rebuild. Both ICCAT and IOTC are concerned over the stock status of yellowfin
tuna. Furthermore, there is concern by the Department as to the origin of the yellowfin tuna
caught by the tuna pole fishery. The albacore stock assessment conducted by ICCAT in 2011
indicated that for the stock to rebuild catches should not exceed 24 000t. However, South
Africa should strive to fully utilise its 10 000 t shared quota with Namibia. The IOTC consider
the albacore stock to be at risk of overexploitation. Given the above-mentioned concerns
the TAE was frozen at the current effort levels. Lastly, to limit conflict with the traditional
linefish sector on the snoek and yellowtail resources the minimum vessel size restriction of
10 m was maintained.
12. Subsistence Fishery (if applicable)
Not applicable.
13. Recreational Fishery (if applicable)
Within the tuna pole fishery there has been an emerging rod and reel component that
targets large yellowfin tuna (> 45 kg dressed weight) south of Cape Town. South Africa also
has a commercial linefish fishery which opportunistically catches albacore, yellowfin, king
mackerel and shark in the Indian Ocean using rod and reel when linefish species such as kob,
geelbek and slinger are not available. These catches usually only contribute to a small
percentage of the total catch by the linefishery due to the multispecies nature of the fishery.
The recreational fishery uses rod and reel from ski-boats (5-8 m) to target numerous game
fish, including yellowfin, king mackerel and billfish. Although catch and effort data are
unknown for this fishery it is estimated that over 100 t of yellowfin and king mackerel are
landed annually for the Atlantic and Indian Oceans combined. All recreational fishers are
required to purchase a permit and are restricted to a bag-limit of 10 tuna, 5 swordfish and 5
billfish per day, with the sale of catch prohibited. There are further weight restrictions of 3.2
kg for yellowfin and bigeye, 6.4 kg for southern bluefin and 25 kg for swordfish caught.
14. Current Research (Description of various projects, each one clickable to produce
box detailing objectives & responsible officer (brief background of responsible
officer & contact details & publications)
The recent establishment of a large pelagic fishery represents an important milestone in the
development of South African fisheries. However, research activities directed at the large
pelagic species targeted by longline are in its infancy in South Africa and to date only four
dedicated research trips have been undertaken since 2008.
•
A general paper detailing the history and current status of the large pelagic fishery is
planned for 2013.
•
DAFF is collaborating with Natacha Nikolik and Jérôme Bourjea (Chairman of the
Working Party on Billfish) from Institut français de recherche pour l'exploitation de
la mer/French Research Institute for Exploitation of the Sea (IFREMER) on the
GERMON project. The project aims to analyse the population structure of albacore
between the south west Indian Ocean and Atlantic Ocean with the use of genetics.
The project is running from April 2013 to December 2015. Through this collaboration
we hope that South Africa can contribute towards a better understanding of the
stock structure of albacore and to aid the RFMOs in managing the species better.
•
Similar to the GERMON project, DAFF has swordfish genetic samples from the Indian
and Atlantic regions of our waters. A genetic study to ascertain the structure
between the two regions will be conducted in 2013.
•
The ageing of swordfish and albacore from this region of the Indian and Atlantic
Ocean with the use of dorsal spines will be conducted in 2013.
•
Stock assessment sessions for albacore and swordfish will be conducted by ICCAT in
2013. South Africa has to contribute standardised catch-per-unit-effort series for
each species towards the sessions.
•
The Department, with the assistance of NGOs (Birdlife SA) and universities, continue
to assess the impact of longline fisheries on seabirds and investigate various
mitigation and management measures. The Department continues to collaborate
with WWF, University of Washington Seas Grant, and Birdlife SA to assess the
impact of longline fisheries on seabirds, turtles and sharks and to investigate various
mitigation and management measures. A National Plan of Action for seabirds was
also published in 2008, which aimed to reduce seabird mortalities below 0.05
seabirds.1000hooks-1. Good collaboration with the fishing industry, researchers and
managers, continual refining of mitigation measures, the implementation of
stringent management measures through permit conditions, and close monitoring
through the observer programme has resulted in seabird mortalities to decrease and
the mortality rate in 2010 was 0.06 seabirds per thousand hooks and is almost at the
goal identified in NPOA-seabirds.
•
South Africa’s involvement in the South West Indian Ocean Fisheries Programme
(SWIOFP) through Component 4: Assessment and sustainable utilization of large
pelagic resources has provided momentum to our research programme. The primary
focus is to understand the distribution and movement of swordfish, bigeye and
yellowfin tuna within the SWIO region, to which end 15 pop-up archival tags (PATs)
have been provided for deployment on swordfish, yellowfin and bigeye tunas as well
as hook monitors and time depth records for deployment of an instrumented
longline. Prior to the inception of this project two bigeye tuna and four blue sharks
have been tagged with PATs and 441 blue sharks with conventional tags.
In 2010, three yellowfin tuna were tagged with PAT tags provided by SWIOFP. The
three tags popped up and transmitted data earlier than what they were
programmed for, indicating that the animals had died prematurely and the tags had
exceeded their depth limit of 1200m. The trends in the data are yet to be analysed
in detail to understand the cause of these premature pop-ups. Three blue sharks
were also tagged with PAT tags in 2010 and a further two blue sharks were tagged
with SPOT tags in 2011. The Department’s national research cruise in 2011 was a
momentous achievement during which 11 swordfish were successfully PAT tagged in
the SWIO region with SWIOFP tags. Swordfish have proven to be very sensitive to
handling and South Africa is the first country to achieve PAT tagging of swordfish in
this region. Tags have been programmed for either 90 or 180 days. Of the 11 tags, 4
remained on the swordfish for more than 2 months. The results of this study were
presented at the IOTC Working Party for Billfish in 2012 (Document number IOTC2012-WPB10-16).
South Africa aims to conduct further research on the movement of large pelagic
species between the Indian and Atlantic Oceans by placing more satellite (PSAT and
SPOT) tags on animals as well as testing out the more affordable electronic spaghetti
tags. Coupled with movement data, genetic studies on the difference between
swordfish from the two Ocean basins will be explored.
•
Rhodes University (Grahamstown) has collaborated with the Department to
ascertain the stock delineation of yellowfin in the boundary region between the
Indian and Atlantic Oceans by conducting genetic analysis and investigating
movement patterns. The results, which form part of a MSc thesis, have yet to be
released and verified.
•
A study on exploratory live bait permits issued to the tuna pole sector is intended in
2013 to 2013. The aim of the study will be to review a live bait component in South
Africa and to ascertain the effect live bait extraction will have on the Small Pelagics
sector.
•
South Africa has 3 years of instrumented longline data from the dedicated research
cruises which should be analysed from 2013 onwards in a target and bycatch study.
15. Possibly contact details for scientist-in-charge? Ie “Further info”
Wendy West- Large Pelagic Research
[email protected]
Craig Smith- Deputy Director: Pelagic and High Seas Fisheries Management
[email protected]
16. EAF considerations/status; priority issues, challenges, constraints
Seabirds:
South Africa has been collecting data on seabird interaction with its longline fishery since
1998. South Africa’s NPOA for seabirds and was published in 2008. The NPOA-SEABIRDS
specifies a maximum mortality rate of 0.05 birds/1000 hooks, and lays out bycatch
mitigation measures for use in longline fishing. South Africa has introduced a number of bird
mitigation measures through permit conditions since the start of its fishery, including the
compulsory flying of tori-lines, no daylight setting, and use of thawed bait to improve sink
rates, in the tuna fishery. South Africa does not consider the use of line shooters or offal
discard management to be useful in reducing seabird incidental mortality. Furthermore,
South Africa has developed a management plan to reduce seabird by-catch in its longline
fishery in 2008. This plan includes a seabird limit per vessel per year that was implemented
in 2008. Once a vessel reaches 25 birds killed in a year, it must adopt additional mitigation
measures, it has to fly a second tori line and it has to place additional weights on to each
branchline. Since the implementation of seabird mitigation measures and the stringent
monitoring thereof seabird mortality rates has reduced by more than an order of magnitude.
The current seabird mortality rate for 2012 is for the first time in history below the
stipulated rate of 0.05 birds/1000 hooks.
Marine turtles:
The South African government has worked closely with WWF to educate skippers on release
procedures for turtles. The use of circle hooks are encouraged as stated in the permit
conditions, as well as releasing turtles with the use of a dehooker.
Sharks:
The Department has undertaken to terminate targeting of pelagic sharks due to the
following reasons: 1) both blue and mako are threatened species as described by the IUCN;
2) substantial pelagic shark by-catch is expected in the tuna/swordfish fisheries; 3) sharks
are slow growing, mature late, and have low fecundity which makes them more susceptible
to over-fishing, and 4) concerns over ecosystem effects. Under current management, the
bycatch limit has been set at 2 000t dressed weight. Once this limit is reached, fishing in the
large pelagic fishery would stop. The domestic pelagic longline fishery originally only
targeted tuna and swordfish, although shark by-catch was also recorded. Foreign pelagic
tuna-directed fisheries are mostly comprised of Japanese vessels targeting offshore oceanic
species such as mako sharks (Isurus oxyrinchus) and blue sharks (Prionace glauca). Species
that may not be landed include the hammerhead, thresher, silky and oceanic whitetip
sharks. A priority and challenge of the Department is to curb the targeting of pelagic sharks
such as mako and blue sharks.
The NPOA for sharks has been redrafted and gazetted for public comment in August 2011. The
Department is currently finalising this process.
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